Field of the Invention
It is known from common experience that an envelope and/or a folder, the latter item being specifically involved, should have a neat appearance in order to make a good impression, and that this appearance is mainly the manner in which it maintains, or conversely, does not maintain its shape, or the parallelism of its front cover and rear panel. Maintaining a neat appearance is a more demanding requirement when the contents of the envelope/folder varies in number, so that the thickness or bulk is variable and to be accommodated there must be a front cover and rear panel separation.
This problem is addressed in the prior art by the use of gussets. More particularly, the use of unfolding gussets in envelopes to increase the size thereof is well known as exemplified by U.S. Pat. 3,063,618 issued to E. B. Berkowitz for "Expanding Envelope" on Nov. 13, 1962 and U.S. Pat. No. 768,340 issued to W. W. Ormsbee, Jr. for "Envelope" on Aug. 23, 1904. The gussets in the aforesaid are positioned initially inwardly of the envelope and, in such position, interfere with the insertion of commercial literature into the envelope.
Gussets that initially are projected outwardly of the body of the envelope and unfold inwardly towards the body solve the problem noted in connection with the '618 and '340 patented envelopes, and are embodied in U.S. Pat. No. 4,549,688 issued to Ozmon et al. for "Expandable File Folder" on Oct. 29, 1985. But if the two halves of the V shape which define the gusset in the '688 patent do not fully unfold, i.e., only partially unfold, there is absent an edge, which would be the fully unfolded gusset, to hold the contents in place and to prevent slippage of some documents from the stack of documents from a medial location to a position adjacent the outboard edge of the gusset.